Diplomats face a battle against time and precedent as they look toward the next round of talks with Iran on its nuclear program.

The negotiators broke a 15-month stalemate after 10 hours of “constructive” talks in Istanbul on April 14 and agreed to reconvene in Baghdad May 23. Squeezed by U.S. and European Union sanctions, as well as Israeli and American talk of a military strike to prevent it from acquiring atomic weapons, Iran dropped upfront demands and the talks focused almost exclusively on its nuclear program, according to two Western diplomats involved in the negotiations.

The talks risk a repeat of previous failures, with tensions contributing to a jump in Brent crude prices this year. In Israel, Prime Minister Benjamin Netanyahu yesterday criticized the outcome as giving Iran more time to continue enriching uranium, the process capable of producing fuel for a nuclear bomb.

“The real challenge will come in the ensuing rounds of talks, where these principles of engagement will have to translate into concrete steps,” Trita Parsi, president of the National Iranian American Council and author of a new book, “A Single Roll of the Dice: Obama’s Diplomacy with Iran,” said in an interview. “This applies to the West as well, whose ability to lift sanctions will be as instrumental for keeping diplomacy alive as Iran’s willingness to curb its enrichment activities.”